Thermoplastic tubes in the form of squeeze tubes have been commercially available for use in the packaging of toothpaste, shampoo, cosmetics, foodstuffs, and the like. Such tubes may be produced by severing a tube blank from an extruded tubular cylinder, which tube blank has open ends, and forming a head on one end of the tube blank which has a threaded neck or other means for releasably securing a cap on that end of the tube. After filling the capped tube from the other open end, that other open end is then sealed, such as by heat sealing, to protect the tube contents and to complete the filled tube for subsequent sale.
The formation of such thermoplastic squeeze tubes from multi-layered material, or extruded composites, has been found useful in that a barrier layer may be provided, such as an oxygen impermeable layer, which barrier layer prevents escape of essential oils, or the like, from the tube contents, and protects the contents of the tube from discoloration, change in taste, or other detrimental affect of oxygen on the tube contents. The formation of extruded composite tubular cylinders for use in forming tube blanks is a known procedure, as for example described in U.S. Pat. No. 4,723,902, entitled Balanced Flow Extrusion Crosshead and Die Assembly, assigned to the assignee of the present invention, the contents of said patent incorporated by reference herein. As described, such tubes generally have five layers which comprise innermost and outermost layers of a thermoplastic material, a central layer of a barrier polymeric material, and adhesive polymeric material layers, one between the innermost thermoplastic layer and the barrier layer and the other between the outermost thermoplastic layer and the barrier layer. In some instances, where the inner and outer layers adhere sufficiently themselves to the barrier layer, the separate adhesive layers may not be necessary, and a three layered extruded composite tube may be provided.
Such thermoplastic multi-layered tubes have been readily accepted and have been provided with various decorative features and indicia. Indicia, decorative features, and printed matter may be applied to thermoplastic tubes by hot stamping or dry printing, or application of a foil pattern to the tube outer surface. When the thermoplastic multi-layered tube is formed from transparent or translucent material, the tube contents of the tube are visible to the user, but readability of the printed matter on the tube may be less than desired due to the clear background. Or, when the tube has a colored component as one of the layered materials of the multi-layered tube, the readability of the printed matter can be enhanced, but the tube contents are no longer visible to show the amount of contents remaining after partial use by a purchaser. Also, the added step of providing decorative features increases the cost of the tube.
It is an object of the present invention to provide a thermoplastic composite layered tube that has at least one strip of material along the length of the tube that is either transparent, while the remainder of the tube is non-transparent, or is of a color different from the color of the remainder of the tube.
It is another object of the present invention to provide a method of forming a thermoplastic composite layered tube that has at least one strip along the length of the tube that is either transparent, while the remainder of the tube is non-transparent, or is of a different color from the color of the remainder of the tube, during the tube manufacturing process, without the subsequent need to apply ink or foil along the length of the tube.